jikohr Posted June 16, 2021 Share Posted June 16, 2021 (edited) Hi everyone! So, yeah. I keep going back and forth on this one. I've been told it's Nano, but the serration count seems low for Nano (23 per cm distal 25 per cm mesial) and it looks a lot thinner than it actually is on account of a piece of the base missing. That and it's really big for a Nano tooth. Dimensions in mm are 50 x 18 x 11 Dimensions in inches are 1.97 x .71 x .43 The pictures are labeled rex because that's what I though it was originally. This is just bugging me so I'd like a second (or more opinion) just to put my mind at ease once and for all. Edited June 17, 2021 by jikohr Link to comment Share on other sites More sharing options...
Troodon Posted June 17, 2021 Share Posted June 17, 2021 Couple of measurement pointers.. -When you look at serration density its typically done at the midline of both carinae and its the number of denticles over 5mm. -The tooth appears to have some root on it so when you compare it to others it needs to be the crown only not the root area. Guessing root might be +1/4" but it's hard to tell. Does not impact an ID just fyi. Can you take another photo of the base, photo comes across very dark cannot see detail and outer edges on the left side. . 1 Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 Midline means in the middle of the tooth right? I measured 11.5 on the distal side and 12 on the mesial side The scale bar is 5 mm. The exact midline had some (very obnoxious) wear on both sides so I measured the 5 mm just below it. Link to comment Share on other sites More sharing options...
hadrosauridae Posted June 17, 2021 Share Posted June 17, 2021 I'm not an expert, but my first impression is Rex, not Nano. It seems too robust for nano, but hey, I've been wrong before. 1 "There is no shortage of fossils. There is only a shortage of paleontologists to study them." - Larry Martin Link to comment Share on other sites More sharing options...
Troodon Posted June 17, 2021 Share Posted June 17, 2021 1 hour ago, jikohr said: Midline means in the middle of the tooth right No, it's midline of the carina since some mesial carina don't extend to the base. The base shape is one of the primary characteristics we distinguish between the two species. Nanotyrannus bases are rectangular with a pinch in the middle. Your tooths base is more typical of what we see on Trex. 3 1 1 Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 9 minutes ago, Troodon said: No, it's midline of the carina since some mesial carina don't extend to the base. The base shape is one of the primary characteristics we distinguish between the two species. Nanotyrannus bases are rectangular with a pinch in the middle. Your tooths base is more typical of what we see on Trex. Oh Are these good? Link to comment Share on other sites More sharing options...
Troodon Posted June 17, 2021 Share Posted June 17, 2021 Not sure what you are asking? Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 Please pardon my ignorance, I'm having difficulty understanding what you are talking about. The midline of the carina, that refers to that pinch inward that's at the base of Nano teeth right? Link to comment Share on other sites More sharing options...
Troodon Posted June 17, 2021 Share Posted June 17, 2021 Serration density is measured on the midline of the carina. See attached illustration The pinch I'm referring to in in the base of a Nanotyrannus. Hope that helps. 1 Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 (edited) Ooooooooooooooooooohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh The Carina is the line of serrations!!! So to clarify Nano has a noticeable pinch at the base, and sometimes T-rex's mesial side carina doesn't go all the way to the base vs. Nano's which always does. Is this correct? Edited June 17, 2021 by jikohr forgot to ask if correct Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 No wait, you meant that when measuring the midway point to use the middle of the mesial carina and not the middle of the tooth because it might not extend to the base on both species. Link to comment Share on other sites More sharing options...
ThePhysicist Posted June 17, 2021 Share Posted June 17, 2021 48 minutes ago, jikohr said: Ooooooooooooooooooohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh The Carina is the line of serrations!!! So to clarify Nano has a noticeable pinch at the base, and sometimes T-rex's mesial side carina doesn't go all the way to the base vs. Nano's which always does. Is this correct? Christophe Hendrickx defines the carina as: "A sharp, narrow, and well-delimited ridge or keel-shaped structure running apicobasally on the crown and, in some cases, on the root base, and typically corresponding to the cutting edge of the tooth." https://www.jstor.org/stable/24524141?seq=1#metadata_info_tab_contents Nano can have more basal compression, but some T. rex maxillary teeth can have some minor compression as well, which makes smaller maxillary teeth of Nano and T. rex more difficult to distinguish. The extent of the mesial carina I believe is a positional feature rather than related to species. And yes, in measuring the serration density, use the midpoint of the carina, not half the crown height. 1 "Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan "I was born not knowing and have had only a little time to change that here and there." - Richard Feynman Collections: Hell Creek Microsite | Hell Creek/Lance | Dinosaurs | Sharks | Squamates | Post Oak Creek | North Sulphur River | Lee Creek | Aguja | Permian | Devonian | Triassic | Harding Sandstone Instagram: @thephysicist_tff Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 3 minutes ago, ThePhysicist said: Christophe Hendrickx defines the carina as: "A sharp, narrow, and well-delimited ridge or keel-shaped structure running apicobasally on the crown and, in some cases, on the root base, and typically corresponding to the cutting edge of the tooth." https://www.jstor.org/stable/24524141?seq=1#metadata_info_tab_contents Nano can have more basal compression, but some T. rex maxillary teeth can have some minor compression as well, which makes smaller maxillary teeth of Nano and T. rex more difficult to distinguish. The extent of the mesial carina I believe is a positional feature rather than related to species. And yes, in measuring the serration density, use the midpoint of the carina, not half the crown height. Ah, okay I understand. Are there any other distinguishing characteristics between a juvenile rex and nano besides the compression? What about the serration count at the midline of the carina? Link to comment Share on other sites More sharing options...
Paleostoric Posted June 17, 2021 Share Posted June 17, 2021 2 hours ago, jikohr said: Ah, okay I understand. Are there any other distinguishing characteristics between a juvenile rex and nano besides the compression? What about the serration count at the midline of the carina? By my understanding, the base is the main characteristic needed to differentiate between the two since a juvenile T. rex and Nanotyrannus can be similar sizes, making ID difficult sometimes. T. rex is also usually more robust than Nanotyrannus. There's some other more detailed info in this post by Troodon as well if you want to take a look: 1 Link to comment Share on other sites More sharing options...
jikohr Posted June 17, 2021 Author Share Posted June 17, 2021 Thank you all so much!!!! This is all really useful info for me! I'm calling it a rex, and I've gone and reevaluated some other teeth with this info. Link to comment Share on other sites More sharing options...
hxmendoza Posted June 21, 2021 Share Posted June 21, 2021 I agree with @Troodon. It is rex. And it is a right maxillary tooth. Nice pickup! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now